22 



14. Racemes 2-9 inches long, on the main culms 15 



Racemes J-l^ inches long, on branches of a panicle 19 



15. Lower glumes dorsally flattened. Keels broadly winged 



above A. distachyus. 



Lower glume with a narrow groove. Keels not winged 16 



16. Blades very narrow, filiform A. Illifolius. 



Blades linear 1-5 lin. broad 17 



17. Blades rounded or sub-cordate, and sub-amplexicaul at 



the base A. amplectens. 



Blades narrow at the base 18 



18. Culms simple. Blades 1-2 lin. broad 



A. schirensis var. angustilolia. 

 Culms branched. Blades 2-3^ lin. broad ... A. schinzii. 



19. Column of the awn glabrous 20 



Column of the awn pubescent or hirsute 22 



,20. Leaf sheaths quite glabrous. Lower glume of sessile 

 spikelets with a narrow gi'oove from the middle down- 

 wards A. schoenanthus. 



Lower sheaths firm, fugaciously hairy to tomentose at 



the base. 

 Lower glume of the sessile spikelets flattened or con- 

 cave 21 



"21. Keels of lower glume winged above 



A. nardiis var. marginatiis. 

 Keels of lower glume rounded-. Scarcely winged ... 



A. plurinodis. 

 "22. Callus of the sessile spikelets very short or obscure, 



obtuse 23 



Callus of the sessile spikelets acute, up to 1 lin. long, 



densely bearded 30 



•23. Spathes broadly lanceolate to ovate, J-1 inch long ... 



A. cymbarins. 



Spathes narrow linear to lanceolate, 1-3 inches long... 24 



"24. Spikelets of the lowest 2 pairs of peduncled racemes alike 



in form and sex .A. buchanani. 



Spikelets of the lowest pair of the peduncled raceme of 



different sex 25 



"25. Racemes short, 2-5 jointed A. dichroos. 



Racemes long, 5' many jointed 26 



26. Spikelets silvery villous 27 



Spikelets not silvery villous 28 



"27. Tall stout culms. Common peduncles laterally exserted. 



A. aiiptiis. 

 Slender culms. Common peduncles equalling or exceed- 

 ing the spathes \. liirtiis. 



